November 2022 - Bird-users

[PATCH] Bus error on ARMv7 when using OSPF
by Matthew Reeve 18 Dec '24

18 Dec '24

Hi, when using bird 2.0.8 on openwrt 21.02 (and other versions) on a Netgear R7800 router, if the OSPF protocol is used, either v2 or v3, bird immediately crashes on startup with: Fri Jun 11 14:41:11 2021 daemon.info bird: Started Fri Jun 11 14:41:11 2021 kern.err kernel: [ 3500.853248] Alignment trap: not handling instruction f44c0a1f at [<00035848>] Fri Jun 11 14:41:11 2021 kern.alert kernel: [ 3500.853283] 8<--- cut here --- Fri Jun 11 14:41:11 2021 kern.alert kernel: [ 3500.859363] Unhandled fault: alignment exception (0x801) at 0x007e0624 Fri Jun 11 14:41:11 2021 kern.alert kernel: [ 3500.862443] pgd = 0bbef4fd Fri Jun 11 14:41:11 2021 kern.alert kernel: [ 3500.868821] [007e0624] *pgd=5d6ca835, *pte=5c40b75f, *ppte=5c40bc7f This router uses an ARMv7 processor and the issue seems to be to do with memory alignment issues. I've debugged it and traced it to an access to the top_hash_entry struct. I've found that if I add the PACKED macro to the struct definition then it fixes the problem, as per this patch: --- a/proto/ospf/topology.h +++ b/proto/ospf/topology.h @@ -41,7 +41,7 @@ struct top_hash_entry u8 mode; /* LSA generated during RT calculation (LSA_RTCALC or LSA_STALE)*/ u8 nhs_reuse; /* Whether nhs nodes can be reused during merging. See a note in rt.c:add_cand() */ -}; +} PACKED; /* Prevents ospf_hash_find() to ignore the entry, for p->lsrqh and p->lsrth */ Thanks.

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logging via udp
by Alexander Zubkov 13 Dec '23

13 Dec '23

Hello, Made some dirty patch for myself to allow bird to send logs via udp. But it may be useful not only for me, so posting it here. It could be useful when server experiencing high IO-load. As syslog and file operations in bird are blocking, it can be blocked on writing to it for indefinite time, which could lead to various problems like protocol timeouts. So udp logging comes in handy here. The tradeoff is that we can miss some logs if they are not processed in time. You can specify udp log destination like that: log udp [host IP|"hostname"] [port NUMBER|"portname"] ... By default it uses destination ip 127.0.0.1 and port 514. There are some constraints like not much error handling. And this destination replaces file destination, i.e. you can not use those simultaneously and it may leak descriptors and some memory probably if both are specified. It also makes a new socket every time configuration is reloaded even if there is no change in options, but this is not a great deal.

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BIRD show bgp summary for cli
by Roman Bulakh 14 Jun '23

14 Jun '23

Hi, we use BIRD in our environment, and it would be very nice to have some command like `show bgp summary` in juniper. This command show information about peer IP, peer AS, last update, prefixes received/best/exported and last state. Example: bird> show bgp summary Peer AS Last state change Prfx rcvd/best/export State X.X.X.X asXXXX 2021-01-27 6786/6785/109000 Established Y.Y.Y.Y asYYYY 2020-12-16 0/0/0 Passive BGP Error: Hold timer expired The are patch created for BIRD 1.3.4 and 1.3.6, but it would be good to have this in upstream software, without rebuilding and patching. as I understand it, no functionality should be affected by these changes, this is only a visual update for cli. Old patches describes at pages: https://marc.info/?l=bird-users&m=132155489919052&w=2 http://trubka.network.cz/pipermail/bird-users/attachments/20120228/a1499be7… https://bird-users.network.narkive.com/Px6EH3yl/bird-1-3-6-show-bgp-summary…

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Adding more then one bgp community at once
by Борис Коваленко 05 May '23

05 May '23

Hello! Is this possible to add many communites at once? bgp_community.add([(1,1), (1,2)]) is wrong "Setting clist attribute to non-clist value" Regards, Boris -- С уважением, Борис Коваленко

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Expiration for ROA tables until when the VRP is valid?
by Robert Scheck 07 Mar '23

07 Mar '23

Hello all, rpki-client recently implemented the "expires" instruction for roa-sets that OpenBGPD provides [1][2]. As of writing, BIRD does not seem to have something similar...any chance for it? From my understanding this only applies to included ROA files with VRP, not to RTR. [1] https://man.openbsd.org/bgpd.conf#roa-set [2] https://github.com/rpki-client/rpki-client-openbsd/commit/7bf63da6ec80f37bd… Kind regards Robert Scheck

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BIRD 2.0.{7,10} MED not actually send for learned routes if export table on is set
by Inrin 04 Feb '23

04 Feb '23

Greetings, I noticed during setting up a peering that the MED is not actually send to my peer, although bird shows it in the export. We confirmed this via tcpdump on both ends. After debugging a bit, I noticed that this only affects “learned” routes but routes from the static protocol worked just fine. After disabling the “export table” feature, the MED was send out just fine. Is this behaviour expected? This behaviour is reproducible in BIRD 2.0.7 and 2.0.10 with the following scenario (Configs to test are attached): R0 is connected to R1 and R2 R0, R1 and R2 send each one route R0 sets the MED to 300 R1 sets the MED to 100 R2 sets the MED to 200 Setting “export table on;” yields the following results: # Bird shows the MED in the export R0 $ ./birdc s r all export R1 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [static1 02:05:56.604] * (200) Type: static univ BGP.med: 300 198.18.2.0/24 unicast [R2 02:11:51.132 from 198.19.0.2] * (100) [AS4242420002i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420002 BGP.next_hop: 198.19.0.2 BGP.med: 300 BGP.local_pref: 100 R0 $ ./birdc s r all export R2 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [static1 02:05:56.604] * (200) Type: static univ BGP.med: 300 198.18.1.0/24 unicast [R1 02:11:51.133 from 198.19.0.1] * (100) [AS4242420001i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420001 BGP.next_hop: 198.19.0.1 BGP.med: 300 BGP.local_pref: 100 R0 # But on R1, R2 it does not appear for learned routes: R1 $ ./birdc s r all protocol R0 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [R0 02:11:51.133 from 198.19.0.0] * (100) [AS4242420000i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 198.18.2.0/24 unicast [R0 02:11:51.133 from 198.19.0.0] * (100) [AS4242420002i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 4242420002 BGP.next_hop: 198.19.0.0 BGP.local_pref: 100 R1 $ R2 $ ./birdc s r all protocol R0 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [R0 02:11:51.132 from 198.19.0.0] * (100) [AS4242420000i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 198.18.1.0/24 unicast [R0 02:11:51.133 from 198.19.0.0] * (100) [AS4242420001i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 4242420001 BGP.next_hop: 198.19.0.0 BGP.local_pref: 100 R2 $ Setting “export table off;” yield the expected result: R1 $ ./birdc s r all protocol R0 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [R0 03:15:47.147 from 198.19.0.0] * (100) [AS4242420000i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 198.18.2.0/24 unicast [R0 03:15:50.635 from 198.19.0.0] * (100) [AS4242420002i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 4242420002 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 R1 $ R2 $ ./birdc s r all protocol R0 BIRD 2.0.10 ready. Table master4: 198.18.0.0/24 unicast [R0 03:15:50.635 from 198.19.0.0] * (100) [AS4242420000i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 198.18.1.0/24 unicast [R0 03:15:50.635 from 198.19.0.0] * (100) [AS4242420001i] Type: BGP univ BGP.origin: IGP BGP.as_path: 4242420000 4242420001 BGP.next_hop: 198.19.0.0 BGP.med: 300 BGP.local_pref: 100 R2 $

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[PATCH] feature to keep protocol's state while configuring
by Alexander Zubkov 29 Jan '23

29 Jan '23

Hello. I have created a patch (attached) with new protocol option: disabled keep on|off. To keep the protocol's state while loading new config. It is useful when protocols disabled manually in the runtime, but we want to keep that state when loading new config. Patch is attached. I have made it against the current int-new branch.

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[PATCH] Don't treat 0/8 and 240/4 specially in IPv4 classification
by Seth David Schoen 01 Jan '23

01 Jan '23

With the exception of 0.0.0.0 and 255.255.255.255, which have additional special meanings, treat 0/8 and 240/4 as normal unicast addresses by default. This is because some people are experimenting with using these addresses as regular unicast (either for private addresses or for potential future public addresses). On the public Internet, they would still currently be regarded as bogons and one could make (maybe by default) a bogon-filtering rule in bird.conf that would not permit these addresses to be routed, e.g. with a pair of static routes route 0.0.0.0/8 prohibit; route 240.0.0.0/4 prohibit; or simply route 0.0.0.0/8 blackhole; route 240.0.0.0/4 blackhole; Dave Taht, who wrote a prior version of this patch, suggested that in any case it is better to have bogons defined in a configuration file than hard-coded in software. --- lib/ip.c | 7 +++++-- lib/ip.h | 2 +- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/lib/ip.c b/lib/ip.c index 4c5fa47f..e13bbce0 100644 --- a/lib/ip.c +++ b/lib/ip.c @@ -87,8 +87,10 @@ ip4_classify(ip4_addr ad) if (b < 0xe0) { - if (b == 0x00) /* 0.0.0.0/8 This network */ + if (a == 0x00000000) /* 0.0.0.0/32 Unset address */ return IADDR_INVALID; + /* 0.0.0.0/8 is otherwise reserved, but + * some people are using it or trying to */ if (b == 0x7f) /* 127.0.0.0/8 Loopback address */ return IADDR_HOST | SCOPE_HOST; @@ -107,7 +109,8 @@ ip4_classify(ip4_addr ad) if (a == 0xffffffff) /* 255.255.255.255 Broadcast address */ return IADDR_BROADCAST | SCOPE_LINK; - return IADDR_HOST | SCOPE_SITE; /* 240.0.0.0/4 Reserved / private */ + return IADDR_HOST | SCOPE_UNIVERSE; /* 240.0.0.0/4 Reserved / private, but + * some people are using it or trying to */ } int diff --git a/lib/ip.h b/lib/ip.h index 9eef2e16..875b9f5e 100644 --- a/lib/ip.h +++ b/lib/ip.h @@ -245,7 +245,7 @@ static inline int ip6_is_v4mapped(ip6_addr a) #define ipa_is_link_local(x) ip6_is_link_local(x) static inline int ip4_is_unicast(ip4_addr a) -{ return _I(a) < 0xe0000000; } +{ return _I(a) < 0xe0000000 || (_I(a) >= 0xf0000000 && _I(a) != 0xffffffff); } /* XXXX remove */ static inline int ipa_classify_net(ip_addr a) -- 2.25.1

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Calling Bird2 from Python script fails
by Stavros Konstantaras 11 Dec '22

11 Dec '22

Hi all, I am trying to automate Bird2 configuration with Python3 and I faced this strange issue: * If I generate a part of the config which is included in the main config file and then I call “birdc configure” via os.system() function, the new configuration is ignored. * If I generate a full config and I call “birdc configure” via os.system() function, I get the strange error “bird2_control.conf:1:1 No protocol is specified in the config file” Which is strange because the first line of my config is a big comment that can be ignored. * If myself execute ““birdc configure” without touching/changing anything in the config, it is accepted and executed immediately without issues !!! Things I tried so far to overcome the issue: * I used subprocess.run() but didn’t have any luck * Tried to use a 2s sleep between writing the new config and reloading bird2, didn’t work * I used python2 instead of python3 but still didn’t have any luck * I executed “birdc configure” via a BASH script, still didn’t work * User and file permissions checked, now problem. Anyone has experienced this weird problem before and has a suggestion to overcome it? It seems to be a birdc issue and doesn’t like to be called from scripts. FYI, I use Bird 2.0.10 on CentOS 7 and Python 3.6.8 Kind Regards Stavros

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Re: bgp keepalive & hold timers
by Serge G 10 Dec '22

10 Dec '22

Hi, Not sure if it's still relevant, but I just wanted to propose another approach. Instead of comparing configured keepalive with the hold timer received from a peer, it might be more straightforward to add another knob, e.g. "minimum-hold-timer". (as on Juniper https://www.juniper.net/documentation/us/en/software/junos/bgp/topics/ref/s…; Nokia also has similar knob) Reason for this is that (the following is just my opinion) 'keepalive' only configures an interval for keepalive messages. And if we start using the value of keepalive timer to enforce some restrictions on peer's hold timer, this may be confusing. In other words, "minimum-hold-timer" would more clearly indicate our restrictions on hold timers. If I see "minimum-hold-timer 30" in the configuration, I understand that this device has some limitations. If I see "keepalive 10", it doesn't tell me anything about restrictions, only that this device will send keepalives every 10 secs. P.S. I haven't dealt with mailing lists before, so forgive me if I reply to the wrong thread. This is the thread I;m replying to: https://bird.network.cz/pipermail/bird-users/2022-April/016071.html

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